A new political survey in the U.S. shows billionaire real estate mogul Donald Trump pulling into a clear lead in the crowded 2016 Republican presidential nominating contest.

The CNN/ORC poll released Tuesday shows Trump with the national support of 24 percent of registered Republican voters, easily outdistancing his nearest challenger, former Florida governor Jeb Bush, the son and brother of two former U.S. presidents, with 13 percent.

None of the other 15 candidates in the race hit double digits in the survey. Retired neurosurgeon Ben Carson had 9 percent, Florida Senator Marco Rubio and Wisconsin Governor Scott Walker had 8 percent each, with the others following with smaller shares.

The CNN/ORC survey of 1,000 voters was taken over the past few days, a week after a Republican candidate debate. It showed that compared to a July poll, the 69-year-old Trump gained six points.

The outspoken Trump has also boosted his favorability ratings among Republicans, with 58 percent now saying they have a favorable view of him, compared to 50 percent a month ago.

The survey showed Republicans supporting his views over other candidates on improving the U.S. economy, enacting tougher immigration policies and fighting Islamic State insurgents in the Middle East.

Other polls have shown Trump leading in the first two states that will conduct party nominating contests next February, Iowa and New Hampshire.

But Trump's challengers have noted that primary voting is more than five months away and that candidates in presidential nominating contests in years past have often fared well early in surveys only to quickly lose support when it came time for voters to cast ballots.